LONG-TERM RISE OF STORMINESS OF THE BALTIC SEA NEAR POLAND; POSSIBLE ORIGIN AND CONSEQUENCES

Grzegorz Marcin Rozynski, Zbigniew Pruszak

Abstract

Long-term growth of storminess of the Baltic Sea near Poland has been identified for autumn and winter months, particularly for January. This growth is concurrent with the increase of westerly waves in Jan., Feb. and Oct. A vivid relationship between the North Atlantic Oscillation and significant wave height Hs in Jan. suggests it can be a potential driver of storminess growth in that month. For Feb. this relationship is unstable; other months demonstrate no connection toward the NAO. The wave climate in January also exhibits a strong 8-year cycle, very likely to drive 8-year variations of shoreline position, detected previously at a study site. The influence of NAO may manifest an unfavorable regime change in which mightier winter storms will be mostly occurring above freezing in the absence of ice cover. Without that cover vulnerable sandy beaches will be exposed to accelerated erosion from direct and stronger wave attack.